The auxilary water pump in my 91 300E24V thumps every now and then and I can hear it and feel it through the brake pedal too.Car temp is fine and so is everything else.

That sounds very strange, how do you know it's the aux. water pump? Would it be safe to assume your car is right hand drive?

You're right jet my car is a RHD and as far as I know the aux. pump is under the wiper wash container.
Thanx.

I hate to say this but I don't think I can help you much because I'm not familar with RHD vehicles and what the differences are concerning the 124 series. Maybe by replying to this thread, and bringing back up front, someone else might see it and be able to help you. Good Luck.